List the main Linux commands for managing the server, file system, processes, and network.

Basic Linux commands for management:

Server:

• systemctl start|stop|restart|status <service> — manage services.
• journalctl -u <service> — view service logs.
• top or htop — process and load monitoring.

File system:

• ls, cd, pwd — view and navigate directories.
• cp, mv, rm — copy, move, delete files.
• chmod, chown — change permissions and owners.
• df -h — information about free disk space.
• du -sh <folder> — size of a folder.

Processes:

• ps aux — list of processes.
• kill <pid>, killall <process_name> — terminate processes.
• nice, renice — manage process priority.

Network:

• ifconfig or ip addr — network interface information.
• ping <host> — check host availability.
• netstat -tulnp or ss -tulnp — open ports and sockets.
• curl or wget — URL requests.
• iptables — firewall configuration.

These commands cover basic administration and diagnostic tasks.